The present invention relates generally to coated potato products and formulations for coating potato products such as frozen french fries.
Methods for preparing and applying coatings to the outer surfaces of frozen potato products are well known in the art. Murray et al. U.S. Pat. No. 3,597,227 disclose a process in which raw potato strips are coated in a hot aqueous solution of modified gelatinized amylose derived from corn or potato starch. The process is said to produce a finished product which has superior strength and rigidity. Van Patten et al., U.S. Pat. No. 3,751,268 disclose the coating of blanched potato pieces with an ungelatinized unmodified high amylose starch having an amylose content of at least 50 percent. The coated potato strips are deep fat fried during which the starch in the coating is gelatinized.
El-Hag et al. U.S. Pat. No. 4,317,842 discloses the process of dipping blanched potato strips in an aqueous ungelatinized starch slurry to coat the strips, which are next soaked in hot oil to gelatinize the starch in the coating. The strips are then parfried and frozen. The strips may be reheated for consumption by heating in an oven rather than by deep fat frying.
Lenchin et al., WO 85/01188 disclose batters comprising the flour of high amylose corn hybrids for producing microwaveable pre-fried foodstuffs. The use of flours of high amylose corn hybrids is said to provide pre-fried foodstuffs with improved crispness after microwave cooking which otherwise tends to make such products soggy.
Bell et al., U.S. Pat. No. 4,504,509 disclose batter compositions for potato strips comprising crosslinked high amylose corn starch (Hylon.RTM. VII, National Starch and Chemical Corp.) in combination with tapioca dextrin. Lenchin et al., U.S. Patent Nos. 4,595,597 and 4,529,607 and Zallie et al., U.S. Pat. No. 5,281,432 also disclose the use of high amylose corn starch or acetylated high amylose corn starch in french fry enrobing slurries. While high amylose corn starches can provide certain useful properties to french fry enrobing slurries their practical utility is limited by their expense.
Sloan et al., U.S. Pat. Nos. 5,059,435 and 5,141,759 disclose a process for preparing frozen coated potatoes wherein raw potatoes are washed, cut, blanched and partially dehydrated. The cut potatoes are then coated with an aqueous starch slurry comprising 15 to 35% by weight modified ungelatinized potato starch, 2 to 10% by weight modified ungelatinized corn starch, 2 to 10% by weight rice flour and other optional ingredients. The coated potato strips are parfried in oil and then frozen. The frozen strips are prepared for consumption by either finish frying in hot oil, or heating in an oven. The starch coating is said to enhance the holding quality of the ready to consume product and to improve the acceptability of the finished product by increasing the crispness of the outer surface, and helping to maintain the tenderness of the interior of the cut potato. In particular, the potato starch and corn starch are each said to contribute crispness to the coating, and because they are not gelatinized prior to the parfrying step they decrease clumping of the strips during processing. The rice flour is said to provide a desirable tenderness in the finished product.
The Sloan patents teach the use of potato starches which have been modified through known chemical cross-linking processes in order to minimize sticking or clumping of the strips during processing, and coat the potato strips evenly. The Sloan patents disclose as preferred an ungelatinized chemically modified potato starch (K-1010, Penford Corporation, Richland, Wash.) which is crosslinked with phosphorus oxychloride (POCl.sub.3) at an effective level of 980 ppm. (This starch is characterized by a Brabender Amylograph viscosity of 50-100 BU ("Brabender units") when measured at a 9% starch solids concentration for 15 minutes at 95.degree. C.) A chemically modified ungelatinized cornstarch said to be preferred for use in conjunction with the above modified potato starch is said to be Flojel.RTM. 60 (National Starch and Chemical Corp., Bridgewater, N.J.) which is said to contribute crispness to the coating and to produce an optimal result when present in the coating slurry at a concentration of between two and ten percent by weight.
Also of interest to the present application is the disclosure of Wu, et al. U.S. Pat. No. 5,648,110 which discloses use of potato starches with crosslinking levels which are generally higher than 550 ppm as preferred components of starch enrobing slurries. Further of interest is the disclosure of Woerman, et al. U.S. Pat. No. 5,750,168 which discloses preferred starch enrobing slurries containing crosslinked tapioca starches in combination with tapioca dextrins and high amylose corn starch.
References relating to use of starch hydrolysis products include Calder et al., U.S. Pat. No. 5,302,410 and Brusacker et al., U.S. Pat. No. 5,393,552 which teach the use of hydrolyzed starch products such as dextrins and maltodextrins as components of aqueous enrobing slurries. Specifically, the patents disclose contacting blanched potato strips with an aqueous solution which contains from 3% to 12% by weight of a hydrolyzed starch product characterized by a DE less than 12 and preferably from about 2 to 10. The patents specifically disclose the use of maltodextrins having a DE of 6 and teach against the use of maltodextrins having DE values greater than 12 because such hydrolyzate products build up reducing sugars and promote undesirable browning of the final product. The patents further teach that concentrations of the starch hydrolyzate products greater than 12% are undesirable because "at higher concentrations the surface of the potato strips become slightly tacky upon finish frying which promotes undesirable clumping of the potato strips."
Of further interest to the present invention is the disclosure (hereby incorporated by reference) of co-owned U.S. Pat. No. 5,897,898, which is directed to the finding that unexpected crispness can be obtained in a french fry coating composition by utilizing at least 40% by weight (on an as is solids basis) of a hydrolyzed starch characterized by a DE of from 0.2 to 0.8. This was particularly surprising in light of the teachings of Calder et al., U.S. Pat. No. 5,302,410; and Brusacker et al., U.S. Pat. No. 5,393,552 as discussed above.
Of further interest to the present invention is the disclosure of Melvej, U.S. Pat. No. 5,431,944 which discloses a dry batter mix for french fries comprising from about 1.5% to about 9% by weight of a leavening agent and from about 5% to about 40% by weight of a starch blend comprising a high amylose starch, a starch, from about 1% to about 8% by weight dextrin wherein the weight percent in the batter mix is inversely related to the weight percent of the leavening agent, and about 0.1% to about 2% of a food gum. The specification teaches that the batter mix preferably includes about 2% to about 6%, by weight of dextrin and that the dextrin "provides a tender bite and in improved mouthfeel to the reconstituted food product." The patent further teaches that "[t]he particular amount of dextrin included in the batter mix is inversely related to the amount of leavening agent present in the batter mix. Therefore, as the amount of leavening agent in the batter is increased, the amount of dextrin in the batter mix is decreased, and vice versa. The dextrin mitigates the effects of the leavening agent and provides a more tender crispness. However, if too much dextrin is included in the batter mix, the reconstituted food product has a greasy mouthfeel." (Col. 7, lines 18-30).
Stubbs et al., U.S. Pat. No. 5,622,741 disclose starch enrobing slurries for potato products comprising the combination of corn flour, dextrins and dent corn starch wherein the dextrins are utilized as fillers. With its emphasis on corn flour the disclosure narrowly defines the modifications that may be made in the enrobing slurry ingredients.
Accordingly, there remains a desire in the art to provide further improvements in the use of dextrin containing enrobing slurries and further to provide improved properties of smoothness, crispness and extended hold time to enrobing slurries. Additionally, there remains a desire in the art to improve or maintain the properties of enrobing slurries while minimizing or eliminating the use of high amylose corn starch.